Brown thought he had struck back by securing the endorsement of “The Fighter” himself, Micky Ward, before the Lowellian and card-carrying Teamster was enlightened on the Republican’s politics and backed out.

Brown recovered by winning the support of Lowell City Councilor Rita Mercier, a pugnacious and ticket-topping politician in a city where exhibiting the former attribute leads to the latter result.

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Steve Joncas, a Lowell native and former state director for the late US senator from Lowell, Paul Tsongas, credits the local newspaper, The Sun, its conservative editorial page, and the city’s rich ethnic heritage for its vibrant political culture.

“If you go back to the story of the ethnic wars, the Irish who controlled the community were Democratic and so the Greeks and the French were Republicans,” said Joncas. Political divisions and the emotion with which they are maintained, he said, “may have something to do with the city’s roots.”

And Joncas echoed Donahue’s explanation for why Brown and Warren are focused on the city: “Lowell’s going to get attention because it’s 100,000 people and it’s the center of this region.”

The city voted in 2008 for Barack Obama over Republican John McCain by a margin of 65 percent to 33 percent. In November 2010, it backed another Democrat, Governor Deval Patrick, in his bid for reelection against GOP challenger Charles D. Baker, 48 percent to 40 percent.

But eight months earlier, Lowell backed Brown over Democrat Martha Coakley in the race to replace the late Senator Edward M. Kennedy.

Brown carried the city by 52 percent to 47 percent — a perfect bellwether for the statewide result of 52 percent to 47 percent.

Now he and Warren are competing virtually hand-to-hand in the city, each through a campaign office in Lowell and both on the stump.

And the two will definitely be back in town on Oct. 1. Their next debate is at the University of Massachusetts Lowell.

Best of Paul Sullivan

Before he emerged in Boston as a WBZ-AM talk show host, the late Paul Sullivan began writing columns in Lowell for The Sun.

Not surprisingly, given the city’s history, many of them focused on politics, but he also brought his wry and fearless perspective to any number of local happenings.

Five years after Sullivan died of brain cancer, his widow, Mary-Jo Griffin, has compiled the best of the columns into a coffee-table book titled, “Sully: The Words, Wit, and Wisdom of Paul Sullivan.”

It will sell for $25 and be available through Middlesex Community College. The school, in turn, will offer a need-based scholarship to some of its business and communications majors, funded with book sale proceeds.

“He had wanted to do this, and when he knew he wasn’t going to be able to, he said, ‘Hey, can you do this one last thing for me?’ ” Griffin said with a laugh as she recalled the conversation.

She said the project ended up being cathartic as she and Sullivan’s children reached the somber anniversary.

“It was very emotional going through them all,” she said of the columns. “You saw him grow personally, and also the wisdom of the insight on the political landscape he had then, and the way it endures today.”

Glen Johnson is lead blogger for Political Intelligence, available online at www.boston.com/politics. He can be reached at johnson@globe.com. Follow him on Twitter @globeglen.

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